This invention relates generally to wellbore casings, and in particular to wellbore casings that are formed using expandable tubing.
Conventionally, when a wellbore is created, a number of casings are installed in the borehole to prevent collapse of the borehole wall and to prevent undesired outflow of drilling fluid into the formation or inflow of fluid from the formation into the borehole. The borehole is drilled in intervals whereby a casing which is to be installed in a lower borehole interval is lowered through a previously installed casing of an upper borehole interval. As a consequence of this procedure the casing of the lower interval is of smaller diameter than the casing of the upper interval. Thus, the casings are in a nested arrangement with casing diameters decreasing in downward direction. Cement annuli are provided between the outer surfaces of the casings and the borehole wall to seal the casings from the borehole wall. As a consequence of this nested arrangement a relatively large borehole diameter is required at the upper part of the wellbore. Such a large borehole diameter involves increased costs due to heavy casing handling equipment, large drill bits and increased volumes of drilling fluid and drill cuttings. Moreover, increased drilling rig time is involved due to required cement pumping, cement hardening, required equipment changes due to large variations in hole diameters drilled in the course of the well, and the large volume of cuttings drilled and removed.
The present invention is directed to overcoming one or more of the limitations of the existing procedures for forming wellbores.
According to one aspect of the present invention, an expandable tubular assembly is provided that includes one or more tubular members and a layer of a lubricant coupled to the interior surfaces of the tubular members.
According to another aspect of the present invention, a method of coupling an expandable tubular assembly including one or more tubular members to a preexisting structure is provided that includes coating the interior surfaces of the tubular members with a lubricant, positioning the tubular members within a preexisting structure and radially expanding the tubular members into contact with the preexisting structure.
According to another aspect of the present invention, an apparatus is provided that includes a preexisting structure and one or more tubular members coupled to the preexisting structure. The tubular members are coupled to the preexisting structure by the process of: coating the interior surfaces of the tubular members with a lubricant, positioning the tubular members within a preexisting structure, and radially expanding the tubular members into contact with the preexisting structure.
According to another aspect of the present invention, an expandable tubular assembly is provided that includes one or more tubular members, and a layer of a first part of a lubricant coupled to the interior surfaces of the tubular members.
According to another aspect of the present invention, a method of coupling an expandable tubular assembly including one or more tubular members to a preexisting structure is provided that includes positioning the expandable tubular assembly into the preexisting structure, injecting a quantity of a lubricant material into contact with the expandable tubular assembly, and radially expanding the expandable tubular assembly into contact with the preexisting structure.
According to another aspect of the present invention, an apparatus is provided that includes a preexisting structure and one or more tubular members coupled to the preexisting structure. The tubular members are coupled to the preexisting structure by the process of: positioning the tubular members into the preexisting structure, injecting a quantity of a lubricant material into contact with the tubular members, and radially expanding the tubular members into contact with the preexisting structure.
According to another aspect of the present invention, a method of coupling an expandable tubular assembly including one or more tubular members to a preexisting structure is provided that includes coating the interior surfaces of the tubular members with a first part of a lubricant, positioning the tubular members within a preexisting structure, circulating a fluidic material including a second part of the lubricant into contact with the coating of the first part of the lubricant, and radially expanding the tubular members into contact with the preexisting structure.
According to another aspect of the present invention, an apparatus is provided that includes a preexisting structure and one or more tubular members coupled to the preexisting structure. The tubular members are coupled to the preexisting structure by the process of: coating the interior surfaces of the tubular members with a first part of a lubricant, positioning the tubular members within a preexisting structure, circulating a fluidic materials having a second part of the lubricant into contact with the coating of the first part of the lubricant, and radially expanding the tubular members into contact with the preexisting structure.